Thin film electroluminescent displays consisting of electroluminescent capacitive type elements are known to those skilled in the art. The luminous efficiency, which is defined as the light output per unit of power actually dissipated, presently is in the range of 1 to 5 lumens per watt. This power, however, represents only a small fraction of the total power dissipated in charging and discharging the panel capacitance when the driving power supply has a real (resistive) impedance. One known method to circumvent this excessive power loss is to utilize a resonant power supply to recover the energy stored in display capacitance and to use it for the next cycle. The problem which presents itself is how to connect a resonant circuit through switching circuitry to hundreds of rows and column leads of a matrix display. It is to this problem that the present invention is directed.
Accordingly, it is an object of the present invention to provide an improved means of driving an electronic display.
It is another object of the present invention to provide a means for driving an electroluminescent matrix type of display.
Still another object of the present invention is to provide a means of driving an electronic display for alpha-numeric, graphic and video applications powered from a resonant power supply circuit.
And yet another object of the present invention is to provide an improved means for driving matrix displays which reduces power consumption, simplifies drive circuitry and eliminates unintentional energization of undesired elements in the display.
Still yet another object of the present invention is to provide an improved means of driving capacitive type electroluminescent display elements of a matrix display taking into account the capacitive coupling of all the rows and columns of the display.